/*

This file is part of Ext JS 4

Copyright (c) 2011 Sencha Inc

Contact:  http://www.sencha.com/contact

Commercial Usage
Licensees holding valid commercial licenses may use this file in accordance with the Commercial Software License Agreement provided with the Software or, alternatively, in accordance with the terms contained in a written agreement between you and Sencha.

If you are unsure which license is appropriate for your use, please contact the sales department at http://www.sencha.com/contact.

*/
/**
 * @class Ext.util.KeyNav
 * <p>Provides a convenient wrapper for normalized keyboard navigation.  KeyNav allows you to bind
 * navigation keys to function calls that will get called when the keys are pressed, providing an easy
 * way to implement custom navigation schemes for any UI component.</p>
 * <p>The following are all of the possible keys that can be implemented: enter, space, left, right, up, down, tab, esc,
 * pageUp, pageDown, del, backspace, home, end.  Usage:</p>
 <pre><code>
var nav = new Ext.util.KeyNav("my-element", {
    "left" : function(e){
        this.moveLeft(e.ctrlKey);
    },
    "right" : function(e){
        this.moveRight(e.ctrlKey);
    },
    "enter" : function(e){
        this.save();
    },
    scope : this
});
</code></pre>
 */
Ext.define('Ext.util.KeyNav', {
    
    alternateClassName: 'Ext.KeyNav',
    
    requires: ['Ext.util.KeyMap'],
    
    statics: {
        keyOptions: {
            left: 37,
            right: 39,
            up: 38,
            down: 40,
            space: 32,
            pageUp: 33,
            pageDown: 34,
            del: 46,
            backspace: 8,
            home: 36,
            end: 35,
            enter: 13,
            esc: 27,
            tab: 9
        }
    },

    /**
     * Creates new KeyNav.
     * @param {Mixed} el The element to bind to
     * @param {Object} config The config
     */
    constructor: function(el, config){
        this.setConfig(el, config || {});
    },
    
    /**
     * Sets up a configuration for the KeyNav.
     * @private
     * @param {Mixed} el The element to bind to
     * @param {Object}A configuration object as specified in the constructor.
     */
    setConfig: function(el, config) {
        if (this.map) {
            this.map.destroy();
        }
        
        var map = Ext.create('Ext.util.KeyMap', el, null, this.getKeyEvent('forceKeyDown' in config ? config.forceKeyDown : this.forceKeyDown)),
            keys = Ext.util.KeyNav.keyOptions,
            scope = config.scope || this,
            key;
        
        this.map = map;
        for (key in keys) {
            if (keys.hasOwnProperty(key)) {
                if (config[key]) {
                    map.addBinding({
                        scope: scope,
                        key: keys[key],
                        handler: Ext.Function.bind(this.handleEvent, scope, [config[key]], true),
                        defaultEventAction: config.defaultEventAction || this.defaultEventAction
                    });
                }
            }
        }
        
        map.disable();
        if (!config.disabled) {
            map.enable();
        }
    },
    
    /**
     * Method for filtering out the map argument
     * @private
     * @param {Ext.util.KeyMap} map
     * @param {Ext.EventObject} event
     * @param {Object} options Contains the handler to call
     */
    handleEvent: function(map, event, handler){
        return handler.call(this, event);
    },
    
    /**
     * @cfg {Boolean} disabled
     * True to disable this KeyNav instance (defaults to false)
     */
    disabled: false,
    
    /**
     * @cfg {String} defaultEventAction
     * The method to call on the {@link Ext.EventObject} after this KeyNav intercepts a key.  Valid values are
     * {@link Ext.EventObject#stopEvent}, {@link Ext.EventObject#preventDefault} and
     * {@link Ext.EventObject#stopPropagation} (defaults to 'stopEvent')
     */
    defaultEventAction: "stopEvent",
    
    /**
     * @cfg {Boolean} forceKeyDown
     * Handle the keydown event instead of keypress (defaults to false).  KeyNav automatically does this for IE since
     * IE does not propagate special keys on keypress, but setting this to true will force other browsers to also
     * handle keydown instead of keypress.
     */
    forceKeyDown: false,
    
    /**
     * Destroy this KeyNav (this is the same as calling disable).
     * @param {Boolean} removeEl True to remove the element associated with this KeyNav.
     */
    destroy: function(removeEl){
        this.map.destroy(removeEl);
        delete this.map;
    },

    /**
     * Enable this KeyNav
     */
    enable: function() {
        this.map.enable();
        this.disabled = false;
    },

    /**
     * Disable this KeyNav
     */
    disable: function() {
        this.map.disable();
        this.disabled = true;
    },
    
    /**
     * Convenience function for setting disabled/enabled by boolean.
     * @param {Boolean} disabled
     */
    setDisabled : function(disabled){
        this.map.setDisabled(disabled);
        this.disabled = disabled;
    },
    
    /**
     * Determines the event to bind to listen for keys. Depends on the {@link #forceKeyDown} setting,
     * as well as the useKeyDown option on the EventManager.
     * @return {String} The type of event to listen for.
     */
    getKeyEvent: function(forceKeyDown){
        return (forceKeyDown || Ext.EventManager.useKeyDown) ? 'keydown' : 'keypress';
    }
});

